Diagnostic and Therapeutic Yield of Imaging Studies in Patients with Dementia and Gram-negative Bloodstream Infections: A Retrospective Cohort Study

Background: Gram-negative bloodstream infections (GNBSI) are life threatening. Appropriate antimicrobial therapy and source control when indicated improve survival. Dementia is an independent risk factor for death and is associated with increased risk for infections, especially in advanced stages. Data about the best diagnostic and therapeutic approaches for patients with dementia and GN-BSI are lacking. Objectives: To evaluate patients with dementia and GN-BSI and determine whether diagnostic imaging improves clinical outcomes. Methods: We performed a retrospective cohort study of adult patients with GN-BSI, during 2019-2022. Patients with or without a diagnosis of dementia were compared. Outcomes were in-hospital mortality and recurrent bacteremia. Demographic, clinical, diagnostic, and therapeutic data were collected and analyzed. Results: A total of 87 patients with dementia and 130 without were included. Patients with dementia received appropriate empirical antimicrobial therapy in 38% of cases compared to 62% of patients without dementia, P < 0.001. Imaging studies were performed in half of patients in both groups. In the dementia group, 17% had abnormal findings that required source control versus 30% in the control group (P = 0.049). Source control was performed in 15% of patients with dementia versus 28% of patients without dementia (P = 0.032). Mortality was 27.6% in the dementia group versus 22.3% in the control group (P = 0.42). Conclusions: In patients with dementia and GN-BSI, imaging studies have lower effect on clinical outcomes. Imaging studies should be performed in selected cases only and not conducted routinely.